Chapter 3 Planning for Production Going Green Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Chapter Highlights

Chapter 3

Planning for Production—Going Green

Permission granted to reproduce for educational use only.

© Goodheart-Willcox Co., Inc.

Chapter Highlights

• The factory system developed in the nineteenth century did not rely on skilled labor.

• The production line created by Henry Ford is one of the most effective manufacturing systems in use.

• Product-oriented manufacturing systems are replacing people-oriented systems.



Chapter Highlights

• Production managers are changing manufacturing systems to manufacture smaller lot sizes with less lead time.

• Push, pull, and kanban are names associated with responsive manufacturing systems.

• Lean manufacturing can become the pathway to green manufacturing.



Introduction

• The basis for a manufacturing system– More than 200 years ago, Adam Smith wrote about

improving manufacturing output through the division of labor.

– In 1798 Eli Whitney demonstrated the value of interchangeable parts.

• In early factories: – Skilled workers were essential. – Quality was based on craftsmanship learned through

experience/apprenticeship.



Unskilled Factory System

• In the nineteenth century, the skilled factory system could not keep up with the demand of the United States.

• Frederick Taylor introduced scientific management as the basis for creating the unskilled factory.– Divided skilled jobs into simple tasks– Defined exactly how to do a

task—motion study– Determined how long it takes to do a task—time study



The Production Line Factory System

• The unskilled factory was seldom well organized and generally chaotic

• Henry Ford created the production line

• The production line provided key three benefits:• Does not require a worker to move the

product to the next workstation—established product flow

• Establishes a specific route and location for workstations

• Created a pace for work to be accomplished



The Production Line Factory System

• However, the real benefit was the third point—which established a manufacturing rate or cycle time to complete a task.



Product-Oriented vs.People-Oriented Factory System

• Manufacturing management in most factories seemed to focus only on the labor cost in the product.

• The objective was to minimize the time it took to complete the task and reduce the cycle time for the task.

• Keeping workers busy was a goal of management.



Product-Oriented vs.People-Oriented Factory System

• The result was a buildup of materials called work in progress (WIP) on the factory floor.

• Management used incentive systems, which significantly increased excess WIP (work in progress).



People-Oriented Manufacturing Systems

• It is important to recognize why excess WIP is a problem. Here is an example. Below is a list of operations to make a simple product. All cycle times are equal.

• This is an ideal situation since it should cause hardly any WIP to develop between workstations.

Task ID Task Standard Cycle Time

1. Stamp out the part in a press. 10 seconds (.00278 hours)

2. Spot-weld a tab on the part. 10 seconds (.00278 hours)

3. Spray paint the assembly. 10 seconds (.00278 hours)




• However, assume a work methods analyst made a change in Task 2, reducing cycle time to 8 seconds. Will this cause a labor savings or just cause an increase in WIP?

Task ID Task Standard Cycle Time

1. Stamp out the part in a press.

10 seconds (.00278 hours)

2. Spot-weld a tab on the part. 8 seconds (.00222 hours)

3. Spray paint the assembly. 10 seconds (.00278 hours)



• What can be done with the extra time available due to the faster cycle time?

• Keeping the worker busy also means keeping machines busy. Either way it has the same result: excess WIP.

• Manufacturing management during the last half of the twentieth century was also focused on machine utilization and efficiency.




• Goldratt and Cox, in their novel The Goal, describe the problems that occur when manufacturers define the effectiveness of a manufacturing system in terms of machine/worker utilization or efficiency.




Product Flow Manufacturing Systems

• Ford’s first production line dealt with a single product. There were no optional colors or “packages.”

• Today automotive production lines have to accommodate a wide variety of options and different models of automobiles.

• However, the manufacturing system developed by Henry Ford’s engineers and technicians had one very significant attribute: it was product flow oriented.



Product Flow Manufacturing Systems (Cont.)

• A product flow system is committed to keeping products moving—being completed and shipped.

• A symptom of a manufacturing system that is not moving product is excess WIP. Parts, assemblies, and partially completed products are examples of WIP.

• Ideally the only WIP should be in a workstation being worked on or arriving just in time (JIT) to be worked on.




• The term just in time has become synonymous with product flow manufacturing systems.

• In the 1980s, manufacturing management became very enthusiastic about JIT, but generally saw it as only an inventory-reduction concept.

• Those companies that tried to implement JIT found that they could no longer operate machines and workstations as decoupled activities.




• Once the operations and processes are tied together, workers or machines might be idled waiting for product to flow into the workstation.



Product Flow Manufacturing with JIT

• Any obstructions to product flow caused a bottleneck or stopped production, since there is no excess WIP to keep downstream workstations busy.

• This interruption immediately focuses everyone’s attention on the machine or workstation causing the obstruction.

• The negative aspect occurs when the organization cannot resolve the problem or prevent it from recurring.



Product Flow Manufacturingwith JIT (Cont.)

• If the problem goes unresolved, excess WIP will creep back into the manufacturing system, destroying product flow.

• JIT creates pain—that is good. It draws attention to product flow problems wherever they occur.



Product Flow Manufacturing Systems

• Product flow has developed into a system called lean manufacturing

• There are five fundamental facets of manufacturing that are common to product flow and lean manufacturing systems: – Quality– Reliability– Setup time– Operator ability– Material availability



• Quality programs in lean manufacturing are based on a systematic approach to eliminate and prevent waste (non-value-added activities) in the production of a product

• Prime examples of non-value-added activities are delays and repair/rework due to defective materials or manufacturing

• Some managers are surprised when they learn that inspection of parts and products is a non-value-added activity

Basis for Lean and Green Manufacturing

Quality




Quality• What is manufacturing’s responsibility for

quality? • It has to create a production system that can

replicate the product design. • A lean manufacturing system replicates the

design with minimal waste. • Engineers/designers have a major role in

ensuring that a product can be successfully manufactured. This activity is called designing for manufacture.



• The equipment and processes selected to make the product must be robust and appropriate for manufacturing the product.

• Manufacturing system robustness means that the system can tolerate the natural variability of the manufacturing environment.


Quality




Quality• The following three characteristics are usually

found in a green manufacturing operation:– An environmental management system– An organized approach for pollution prevention– A lean manufacturing operation that includes Six

Sigma




Waste Reduction• P2 (Pollution Prevention) programs emphasize

reducing or eliminating waste at its source by:– Modifying production processes– Using nontoxic or less toxic materials and supplies– Minimizing the use of resources– Recycling to minimize waste streams




Statistical Process Control• A key element in being able to consistently

replicate design characteristics is the application of Statistical Process Control (SPC).

• This technique provides manufacturers with a simple but effective way to confirm that a manufacturing operation or process is under control.

• When used properly, SPC can detect the onset of a major problem even before bad parts are made.



Basis for Lean and Green ManufacturingStatistical Process Control

1. Establish control. Bring the process or activity into control. Make it capable of replicating consistently, thus making the process or operation predictable.

2. Monitor the activity. Establish a means to:– Visually portray and track the performance of the

activity. – Learn how to recognize when the activity is not

performing normally.

There are three basic steps to institute SPC:



3. Problem solve. Train the manufacturing personnel to be effective problem solvers so they can bring the activity back into control.

Basis for Lean and Green ManufacturingStatistical Process Control

There are three basic steps to institute SPC:



Basis for Lean ManufacturingReliability

• Delays and interruptions due to machines and tools breaking are common reasons for lower-than-expected production output.

• Manufacturing organizations long ago established maintenance departments to respond to these unplanned interruptions of work.




• This approach is called breakdown or reactive maintenance. This is a cost-adding solution. To overcome these interruptions:– Production departments create safety stocks (excess

WIP) of production materials to keep running or to keep people busy.

– Production departments use overtime to “catch up” once the repaired machine is back in production.




• In 1950, Japanese engineers started what should have been an obvious concept. They instituted a maintenance program based on following the machine manufacturers’ recommendations.

• That approach was called preventive maintenance.




• The approach had an unusual feature—it required operators to take an active role in maintaining their equipment (oil, clean, etc.).

• The maintenance department and the people operating the equipment worked in partnership to prevent equipment breakdowns.




• In the 1960s and 1970s, a more effective approach was developed called productive maintenance.

• This method involved the maintenance department and the machine operators, but it brought in another group – manufacturing engineers and technicians.




• These engineers/technicians quantified the reliability of the equipment and determined their mode of failure. Productive maintenance focused on improving equipment reliability.

• The preventive maintenance schedule was changed to respond to the probability of failure under actual production stress. This approach also eliminated many unnecessary preventive maintenance activities.




• Total productive maintenance or total participation maintenance is based on preventive maintenance techniques and diagnostic analysis of the equipment.

• Cleaning equipment is an effective diagnostic activity. This builds on the operator’s role and frequently detects symptoms of problems that could cause a breakdown.– As an example oil leaks, loose bolts, partially clogged

filters are examples of what can be found while cleaning.




• Involving people not familiar with the equipment and its operation can help too. Examples are:– Material suppliers can provide useful suggestions

when they see how their product is used in the manufacturing process.

– Suppliers of generic replacement parts should be asked to look at worn or failed parts and make suggestions for improvement.



Basis for Lean ManufacturingSetup Reduction

• Downtime caused by setup or changeovers is the same as a machinery breakdown in a product flow system.

• Setup reduction, the third facet of lean manufacturing.

• In the past, managers have grouped like parts together to increase the length of a production run.




• This does not reduce the time it takes to do a setup; it merely reduces the frequency of setups.

• Unfortunately, this approach also results in bigger lot sizes, more WIP, and often extends the lead time for a customer’s order.




• Successful companies have organized themselves specifically to reduce setup time.

• They approach setup reduction the same way a NASCAR team views a pit stop. It’s a team task, special tools are needed, and each person involved has specific responsibilities.

• Reducing setup times aims at improving product flow. It also has a major effect in making the manufacturing process more responsive.




• In the 1980s and 1990s, managers talked about manufacturing systems handling a lot size of one.

• Setups and changeovers were done so quickly that they did not impede the flow of product.



Basis for Lean ManufacturingSetup Reduction Procedure

• Here is one procedure that has been used to reduce/eliminate setups:– Form a setup team, which will include the machine

operators, setup people, and plant/production engineers.




• Establish baselines. – Determine how long it now takes to do a setup. – Calculate the target manufacturing lot size. This is

based on customer order quantities. – Calculate the number of setups needed per shift to

meet the target manufacturing lot size. – Determine the target setup time.

• Divide the free machine time during a shift by the number of setups per shift to get the target setup time.




• Video record the current setup process so it can be analyzed.

• Separate external from internal tasks– External tasks are setup tasks that can be

accomplished while the machine is still operating and do not add to the downtime.

– Internal tasks require shutting down the machine. – Take advantage of this difference and focus on

reducing or eliminating the tasks that keep the machine from producing product.




• The setup reduction team needs management’s support and insistence to develop an innovative solution to achieve the target setup time.



Basis for Lean ManufacturingOperator Ability

• This facet has been called operator self-control or Jidoka, which in Japanese is loosely interpreted as autonomous defect control.

• Ensuring that each person is able to fulfill this responsibility is an essential building block in creating a lean manufacturing environment.

• Each individual is a manager and must be able to effectively manage his or her own work.




Therefore, to manage the assigned work, each person must possess the knowledge and skill to:•Do the task correctly.•Recognize that the materials being used meet the required standards.•Determine that the tools, equipment, etc. to do the work are in proper working order.




Therefore, to manage the assigned work, each person must possess the knowledge and skill to:•Recognize if the task is not being done as it should be and be willing to take corrective action. •Obtain help to solve the problem when the problem cannot be corrected with the resources at hand.•Never let a problem/defect move on in the manufacturing process.



Manufacturing SystemPush Systems—Pull Systems

• The terms push and pull describe how a product moves through a factory.

• When an order is received, a push system(MRP system) begins by ordering materials, then establishing a start date to begin production based on when the materials will be available.

• Once materials are available, the push system schedules the order through the plant from the starting operation to the final shipping point.




• Push systems “push” the product through the factory.

• Pull systems try to respond immediately by shipping the order when it is received.

• Shipping the order then creates a demand that moves back up the production line to replace what has just been shipped.




• For a pull system to be responsive, work-in-process must be available at every operation involved in the production of the product.

• In practice, a pull system has proven to be very responsive and effective in synchronizing production activity with demand.



Pull System

6. Fabricated component placed in storage space in Final Assembly

8. Raw materials issued

4. Tote pan returned with completed unit

7. Empty tote pan 3. Empty tote pan

Raw Material

Warehouse

Component Fabrication

Final Assembly

Shipping

1. Customer Order

2. Order Shipped

5. Empty storage space

9. Material order to vendor



Kanban Approach

• The Kanban signal to initiate production consists of a card and a container (tote pan or storage space). Here’s how it works:– When a using department withdraws a container of

parts, the card previously attached to it by the producing (upstream) department is detached and placed in a collection box.



Kanban Approach

• When the most recently emptied container for the same parts is returned to its producing department, the card from the collection box is attached to it

• When the producing department receives this empty container, the card is removed and placed into a recently manufactured container, full of parts, that is then sent to the using department

• This process repeats itself over and over again



Summing Up

• Lean and green manufacturing is a strategy to enable manufacturers to produce products with a minimum of waste

• The goal of lean manufacturing is to effectively produce what the customer requires with a minimum of waste or delay



Summing Up

• A key characteristic of a lean manufacturing facility is robustness, meaning that it is able to function effectively even under the changing circumstances that occur in the day-to-day operation of the factory

• Reliability and quality are also traits of a lean manufacturing facility. Reliability includes people that can be depended on to do what needs to be done as well as suppliers that deliver the right materials on time all the time.



Summing Up

• Implementing programs that will ensure that equipment does not break down unexpectedly, as well as developing and maintaining a quality process to prevent defects, are important parts of a successful lean manufacturing strategy



Summing Up

• The concept of JIT (just-in-time) has become associated with lean manufacturing because it minimizes or eliminates excess work in process, which will result in a reduction of inventory—an important objective



Summing Up

• However, JIT has a more significant role to perform for lean manufacturers. JIT ensures that any problem impacting product flow will immediately become apparent by causing an interruption in production.



Summing Up

• This interruption occurs because JIT eliminates the extra stock to replace defective parts, prevents stocking surplus inventory to cover a supplier’s missed shipment, or maintaining an emergency stock to bridge the time it takes to fix a broken down machine



Summing Up

• JIT means the manufacturing system does not have any “fat” to hide problems when they occur. Therefore, JIT is an alarm system for management



Summing Up

• An EMS(Environmental Management System) creates and maintains a continuous cycle of planning, implementing, reviewing, and improving manufacturing processes and operations



Glossary

• Cycle time– The time it takes to complete a task on one unit.

• Decoupled– Making a task an independent activity.

• Excess WIP (work in progress)– If the part or assembly is not being worked on, having

value added, then it becomes excess WIP.



Glossary

• Jidoka– Each man and woman in the manufacturing process is

responsible for creating and maintaining defect-free product flow.

• Just in time (JIT) manufacturing– A philosophy that eliminates excess inventory by placing

the burden directly on suppliers to deliver parts or materials of an agreed-upon quality at a specified time and in the desired quantity.



Glossary

• Kanban– The trigger (usually a card attached to a bin) used to

start production in a pull system. Kanban literally means “card” in Japanese.

• Operator self-control– Each man and woman in the manufacturing process is

responsible for creating and maintaining defect-free product flow.



Glossary

• Preventive maintenance– A maintenance approach based on following the

manufacturers’ recommendations about the care that should be given to production equipment.

• Pull system– System that tries to ship an order when it is received,

creating a demand that moves up the production line to replace what has just been shipped.



Glossary

• Push system– When an order is received, materials are ordered and

then a start date is established to begin production based on when the materials will be available.

• Reactive maintenance– A maintenance approach in which maintenance

departments are ready to respond to unplanned interruptions of work by stocking spare parts and creating “safety stocks” (excess WIP) of critical production materials.



Glossary

• Statistical process control (SPC)– Technique that provides manufacturers with a way to

confirm that an activity is under control. It consists of three steps: establish control, monitor the activity, and provide for problem solving.

• Work in process– Parts or components that are moving through a

manufacturing operation. WIP is the stage between raw materials and finished goods.

Documents

Chapter 3 Planning for Production Going Green Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Chapter Highlights